Blame me for Iraq mistakes - Bush

American president George Bush personally took the blame for mistakes in the war in Iraq as he announced he would send 21,500 extra US troops there.

Unveiling his long-awaited new strategy in a prime-time TV address to the nation, a chastened-looking Mr Bush pledged that previous errors would not be repeated.

This time there would be enough troops to hold neighbourhoods that had been cleared of terrorists and militants rather than let "terrorists and insurgents" return, and fewer restrictions on US and Iraqi forces, he said.

The president admitted: "The situation in Iraq is unacceptable to the American people - and it is unacceptable to me.

"Where mistakes have been made, the responsibility rests with me."

The US had not expected the devastating sectarian violence of the last year and Iraq's young democracy was now "fighting for its life".

Mr Bush said sending more soldiers at this point would hasten the day when troops could begin coming home, whereas pulling US forces out would cause the Iraqi government to collapse, and provoke "mass killings on an unimaginable scale".

A total of 17,500 combat troops will be sent to Baghdad, with the first of five brigades arriving by Monday.

Some 4,000 Marines will go to Anbar Province, a base of the Sunni uprising and foreign al Qaida fighters.

The additions will bring the total number of US troops in Iraq to 153,500, close to the all-time high of 160,000, at a cost of 5.6 billion dollars.